You could just include something like a "If accessing from a mobile device, please click here" link in the email. Just use HTML in the email to mask the full URL.
<a href="http://server/mobile.framework/">If accessing from a mobile device, please click here</a>
That is what I have done in the past. It doesn't take them directly to the ticket like the process approver link will, but it'll get them to the mobile site where they can find the ticket.
There are two ways to make Web Access "mobile". First is to use a separate URL which specifically specifes in the config for that instance to always be mobile and it sounds like this is what you are doing. You can also however have specific devices always display the mobile version by going to a config URL from the device to add it to a list. You could add your Blackberrys to this on your main Web Access instance so they don't need to use two different URLs.
For more details see the section called "Configuring Mobile Web Desk" in the setup guide here: LANDesk Service Desk Suite 7.5 Service Pack 1 Setup
I've not had chance to look at these yet but thanks for your responses.
i will let you know how i get on when i have chance to test this.